VC++ 网络编程总结（二）

2、基本的Windows Socket API编程

• 需要在程序中添加下面的包含语句：#include <winsock2.h>   #pragma comment( lib, "WS2_32" )
• 使用Vc++编译时需添加编译链接依赖项ws2_32.lib库
• 协议寻址

     在winsock中，应用程序通过Sockaddr_in 结构来指定IP地址和服务端口信息：

      sockaddr_in internetAddr;

      int nPortID = 5320;

      internetAddr.sin_family = AF_INET;

      internetAddr.sin_addr.s_addr = inet_addr(“202.202.42.88”);

      internetAddr.sin_port = htons(nPortID);

    ip地址不容易记忆，还提供了许多地址和名称解析函数如gethostbyname,gethostbyaddr等

2.1常用函数

                                

2.2 TCP实例应用

=======客户端======

#include <stdio.h>
#include <winsock2.h>
#pragma comment (lib,"WS2_32")

int main(int argc, char* argv[])
{
    SOCKET sock;
    struct sockaddr_in sa;
    int err;
    int servport = 5555;
    char buff[256];

    int len;
    WSADATA ws;

    //初始化WinSock
    if(WSAStartup(0x0101,&ws) != 0)
    {
        printf("WSAStartup() failed!
");
        exit(-1);
    }

    //创建套接字
    sock =socket(AF_INET,SOCK_STREAM,0);
    //定义服务器地址结构
    memset(&sa,0,sizeof(sa));
    sa.sin_family = AF_INET;
    sa.sin_port = htons(servport);
    sa.sin_addr.s_addr=inet_addr("127.0.0.1") ;

    //链接服务器
    err=connect(sock,(const sockaddr*)&sa,sizeof(sa));

    //接收欢迎词
    memset(buff,0,sizeof(buff));
    len =recv(sock,buff,sizeof(buff),0);
    printf("%s
",buff);
    closesocket(sock);
    WSACleanup();
    return 0;
}

=======服务器=======

#include <stdio.h>
#include <winsock2.h>
#pragma comment (lib,"WS2_32")

int main(int argc, char* argv[])
{
    SOCKET servsock,clisock;
    struct sockaddr_in sa;
    struct sockaddr_in cliaddr;
    int servport = 5555;
    char buff[256];
    WSADATA ws;
    int len,err;

    //初始化Winsock
    if(WSAStartup(0X0101,&ws) != 0)
    {
        printf("WSAStartup() failed!
");
        exit(-1);
    }
    //创建套接字
    printf("Create Socket...
");
    servsock = socket(AF_INET,SOCK_STREAM,0);

    //填充服务器地址结构
    memset(&sa,0,sizeof(sa));
    sa.sin_family = AF_INET;
    sa.sin_port=htons(servport);
    sa.sin_addr.s_addr = inet_addr("127.0.0.1");

    //绑定套接字到服务器地址结构
    printf("Binding...
");
    err = bind(servsock,(const sockaddr*)&sa,sizeof(sa));
    
    if(err != 0)
    {
        fprintf(stderr,"Bind failed:%d
",WSAGetLastError());
        exit(-2);
    }

    //监听套接字
    printf("Listeing...
");
    err = listen(servsock,5);
    if(err != 0)
    {
        fprintf(stderr,"Listen failed:%d
",WSAGetLastError());
        exit(-3);
    }

    //等待连接请求
    printf("Waiting Request...
");
    len = sizeof(cliaddr);
    clisock =accept(servsock,(struct sockaddr*)&cliaddr,&len);
    printf("Accept Client:%s:%d",inet_ntoa(cliaddr.sin_addr),ntohs(cliaddr.sin_port));
    
    sprintf(buff,"Welcome %s",inet_ntoa(cliaddr.sin_addr));
    send(clisock,buff,strlen(buff),0);
    closesocket(clisock);
    WSACleanup();

    return 0;
}